In the past, this type of large embroidering machine with embroidery lengths of 10 m, 15 m to 21 m has had a two-story design, i.e., two horizontal rows of embroidering positions. Two corresponding fabric lengths being embroidered were positioned one above the other. This achieves twice the number of stitches per minute or per hour compared with a single-story machine. Since the embroidering height (the height of the material being embroidered in a stretcher) was increased from originally less than 40 cm to 120 cm or more, large embroidering machines have become increasingly taller. So as not to require extreme building heights and so as to permit reasonable servicing of the two stories, the machines were designed in such a way that a longitudinal trench in the foundation of the machine is provided in the center axis of the machine, into which the lower portion of the stretching frame can be dropped during embroidery.
As a consequence of this design, the front and back sides of the machine are separated by the trench, which has a depth of up to 1 m. The stability of the machine consequently cannot be assured by the frame, but must be assumed by the foundation. When the floor conditions are unfavorable, considerable expense may be necessary to provide a sufficiently rigid foundation. Insufficient rigidity of the foundation may lead to deformation of the machine, making further operation impossible.
This conventional design also necessitates that the machines be assembled at the site of operation, since a large embroidering machine forms a stable unit integrally with its foundation. Preassembly by the manufacturer is limited to small, self-contained structural units. Final assembly at the operational site may take from 6 to 12 weeks.
Any change in site of such large embroidering machines is an expensive undertaking. The machine must not only be disassembled, but must also be carefully removed from the foundation and reassembled on a new foundation at the new site.
Such a design, with a deep trench for the stretching frame, requires the front and back parts of the machine to be connected at either end with lateral shields. The result is that the sides become so built up that sideways introduction and removal of the fabric webs is difficult.
A two-story design is also the source of considerable difficulty in the maintenance of the machine. Gangways with landings and ladders or with platform lifts, along with the corresponding safeguards, must be installed to serve the upper story. The expense in terms of time and personnel is considerable.